Background:: Screening for bowel cancer using the guaiac faecal occult blood test offered by the NHS Bowel Cancer Screening Programme (BCSP) is taken up by 54% of the eligible population. Uptake ranges from 35% in the most to 61% in the least deprived areas. This study explores reasons for non-uptake of bowel cancer screening, and examines reasons for subsequent uptake among participants who had initially not taken part in screening. Methods:: Focus groups with a socio-economically diverse sample of participants were used to explore participants' experience of invitation to and non-uptake of bowel cancer screening. Results:: Participants described sampling faeces and storing faecal samples as broaching a cultural taboo, and causing shame. Completion of the test kit within the home rather than a formal health setting was considered unsettling and reduced perceived importance. Not knowing screening results was reported to be preferable to the implications of a positive screening result. Feeling well was associated with low perceived relevance of screening. Talking about bowel cancer screening with family and peers emerged as the key to subsequent participation in screening. Conclusions:: Initiatives to normalise discussion about bowel cancer screening, to link the BCSP to general practice, and to simplify the test itself may lead to increased uptake across all social groups.